Limiting child selection

Hi there,

Thanks for an amazing module.

I am using it for specs for cars:

Doors
-4 doors
-5 doors

Seats
-4 seats
-7 seats

etc....

I would like to limit the selection of child terms, allowing only one child per parent to be selected.
Is that possible? I have looked in the settings but can't seem to find it.

If I set the main limit to 1, I can only select one term in totality.
However, I would like to select one child per parent. At the moment, I can select all the children, which messes up my plan.

Any help on how to ensure only one child can be selected?

Thanks in advance